PPC doesn't supported VLA with large alignment. This was

[oota-llvm.git] / lib / Target / PowerPC / PPCFrameInfo.h

diff --git a/lib/Target/PowerPC/PPCFrameInfo.h b/lib/Target/PowerPC/PPCFrameInfo.h
index 65f113e6fb9aff31490282eb820efd225acea542..7587b0359816816539892548ba3f3e3b9ede0ad4 100644 (file)
--- a/lib/Target/PowerPC/PPCFrameInfo.h
+++ b/lib/Target/PowerPC/PPCFrameInfo.h
@@ -42,14 +42,15 @@ public:
   /// frame pointer.
   static unsigned getFramePointerSaveOffset(bool isPPC64, bool isDarwinABI) {
     // For the Darwin ABI:
-    // Use the TOC save slot in the PowerPC linkage area for saving the frame
-    // pointer (if needed.)  LLVM does not generate code that uses the TOC (R2
-    // is treated as a caller saved register.)
+    // We cannot use the TOC save slot (offset +20) in the PowerPC linkage area
+    // for saving the frame pointer (if needed.)  While the published ABI has
+    // not used this slot since at least MacOSX 10.2, there is older code
+    // around that does use it, and that needs to continue to work.
     if (isDarwinABI)
-      return isPPC64 ? 40 : 20;
+      return isPPC64 ? -8U : -4U;
     
     // SVR4 ABI: First slot in the general register save area.
-    return -4U;
+    return isPPC64 ? -8U : -4U;
   }
   
   /// getLinkageSize - Return the size of the PowerPC ABI linkage area.
@@ -90,6 +91,17 @@ public:
   // With the SVR4 ABI, callee-saved registers have fixed offsets on the stack.
   const SpillSlot *
   getCalleeSavedSpillSlots(unsigned &NumEntries) const {
+    if (TM.getSubtarget<PPCSubtarget>().isDarwinABI()) {
+      NumEntries = 1;
+      if (TM.getSubtarget<PPCSubtarget>().isPPC64()) {
+        static const SpillSlot darwin64Offsets = {PPC::X31, -8};
+        return &darwin64Offsets;
+      } else {
+        static const SpillSlot darwinOffsets = {PPC::R31, -4};
+        return &darwinOffsets;
+      }
+    }
+
     // Early exit if not using the SVR4 ABI.
     if (!TM.getSubtarget<PPCSubtarget>().isSVR4ABI()) {
       NumEntries = 0;